1. Field of the Invention
The invention relates to a gear shift lock device for a vehicular automatic transmission in which a gear shift action is rendered inoperative while a parking brake pedal is not applied.
2. Description of Prior Art
In a gear shift lock device for a vehicular automatic transmission, a gear shift action is usually rendered inoperative when not applying a parking brake pedal as shown in FIG. 12. A detent pin J1 of a gear shift lever engages with a detent cam J3 which is provided on a detent plate J2 so as to provide a plurality of ranges including a parking range in combination with an operation of the gear shift lever.
The gear shift lock device has a select plate J4 having an engagement member J5, and is provided rotationally between a lock position in which the engagement member J5 lodges the detent pin J1 to lock, the gear shift lever in the parking range, and an unlock position in which the engagement member J5 is dislodged from the detent pin J1.
When the engagement member J5 is engaged with the detent pin J1, the select plate J4 is adapted to engage with a lock pin J7 which is connected to an end of a shift lock cable J6 so as to move in association with a parking brake pedal. When the parking brake pedal is applied, the lock pin J7 is dislodged from the select plate J4 to allow the plate J4 a rotational movement so as to operate the gear shift lever from the parking range to other ranges.
Since the detent pin J1 is adapted to move downward with pushing operation of a button which is attached to a knob of the gear shift lever, pushing the button makes the detent pin J1 move downward to impart the rotational movement to the select plate J4 as shown by an arrow (A) in FIG. 12 when the parking brake pedal is not applied (i.e., a gear shift lock is working).
The rotational movement of the select plate J4, exerts against the lock pin J7 to cause a prying force against a cylinder guide J8 which encloses the lock pin J7.
The prying force, thus generated, would be one of the causes to invite a mulfunction with the pushing operation of the button in the prior gear shift lock device.
Therefore, the present invention has made with the above drawbacks in mind, it is a main object of the invention to provide a gear shift lock device for a vehicular automatic transmission which is capable of preventing the prying force from occurring on a lock pin so as to maintain a good function even when a rotational force is transmitted to the select plate by pushing a button while a gear shift lock is working.